Smoke and ash are sucked back into the chimneys, bodies are removed from the ovens, naked men and women are herded out of the gas chambers, and trains full of Jews roll backward through the gates of Auschwitz. And so on.

I thought of Amis' book last week while following the interesting public debate over a fundamental question: When is the right time to learn about the Holocaust?

The question was raised by NBC's airing of Schindler's List, Steven Spielberg's graphic depiction of the Nazi extermination of 6 million Jews - minus the 1,200 saved by Oskar Schindler.

The Orlando Sentinel published a ''My Word'' column from an Orlando father who agonized over the issue but ultimately prohibited his 12-year-old son from watching the movie.

''Guard your children's eyes and minds lest they become calloused at a tender age by the brutality of this world's sin,'' he wrote. ''They will learn of it in due time. What innocence they do have we should be zealous to protect.''

It was an eloquent appeal. I mulled it over. Then I thought of Time's Arrow.

If it were possible to rewind history, would we arrange for every 12-year-old in Nazi Germany to view Schindler's List? I think so.

It probably wouldn't stop the Holocaust, but it might put a damper on recruiting for the Hitler Youth and produce a few more Oskar Schindlers.

This is the dilemma about childhood and innocence: It also is prime time for inculcating moral and ethical codes. Attitudes harden much earlier than arteries.

Tess Wise is executive director of the Holocaust Memorial Resource and Educational Center of Central Florida. She's also a Holocaust survivor.

Wise thinks Schindler's List is too intense for elementary school students. ''But I feel very strongly that middle-school children are capable of integrating this sort of art and information,'' she said.

Wise has two middle-school-age grandchildren, ages 12 and 13, who watched the movie. ''They really were very taken by it,'' she said.

Wise had one misgiving about the NBC showing. ''I believe the film absolutely required a debriefing afterward. And it would be helpful if prior to the film there was some preparation for viewing it.''

In a bit of scheduling kismet, the airing of Schindler's List coincided with the Central Florida premiere of Rosewood, which tells the story of a black town in Florida burned to the ground by racists.

When is the right time to learn about this miniature American holocaust?

Rosewood is a movie many parents probably will hesitate to take their children to because of the vividly depicted violence inflicted on the black residents of Rosewood.

But if we could rewind history, wouldn't we want every white man in that mob to go back and see Rosewood when he was a 12-year-old boy - like the boy in the movie who left home because he was ashamed of his father's racist rampage? I think so.

Maybe it would have stopped the burning. Surely it would have produced more white men of conscience like the one played by Jon Voight in Rosewood.

So I would encourage parents to take their older children to see Rosewood, providing historical context beforehand and a ''debriefing'' afterward as Tess Wise suggests.

Finally, in the interest of full disclosure I should acknowledge my bias. My mother is a Holocaust survivor from the Ukraine. Her family was on a death march out of their village when her father bribed a German soldier with a gold watch to turn his head.

When he did, my mother and her sister ran for their lives. They never saw their parents again. My mother was 13 years old, her sister, 11. There is no ''right'' time to learn about a holocaust.